Addition agent for lubricants



Patented Apr. 20, 1943 UNITED STATS AT E ADDITION AGENT FOR LUBRICANTS of Delaware No Drawing. Application December 26, 1941, Serial No. 424,548

7 Claims.

This application is a continuation-in-part of our copending application Serial No. 376,380, filed January 28, 1941.

This invention relates to improved compositions of matter comprised of normally liquid or solid organic substances containing an added ingredient which improves their properties in one or more important respects. More particularly,

- it relates to improved lubricating oil and greases.

Within recent years many difierent substances have been added to lubricating oils and greases to impart to them properties not ordinarily possessed by such materials or to improve certain characteristics already possessed by them or to imhibit the development of undesirable properties latently present in the oil. It is customary, for example, where the lubricant is subjected to oxidizing conditions as. in an automobile crankcase, to add an agent which will inhibit oxidation of the oil. It is also customary to improve the protective efiect on rubbing surfaces by the addition of certain substances which reduce corrosive or abrasive wear, scufiing, and seizure which normally follow a break in the continuity of the lubricating films due to extreme pressure or unfavorable speed conditions.

We have discovered that allophanates and certain related compounds are useful in bringing about various improvements in hydrocarbon oils when added thereto in relatively small amounts.

Therefore, it is an object of this invention to provide addition agents which, when added to lubricating oil, Diesel fuel oil, etc., will reduce wear, scoring and seizure of metal bearing surfaces. Another object is to reduce corrosiveness of hydrocarbon oils.

According to this invention, allophanates which are of the general formula N-R; Rs

are added to lubricating oils and greases. In this formula X represents oxygen or sulfur, R2 and R: are hydrogen or hydrocarbon radicals, preferably hydrogen, and R1 may be an aliphatic, alicyclic, aromatic, or mixed cyclic and chain radical.

The hydrocarbon radicals R2 and R3 may contain (preferably not more than one) polar, neutral, or basic substituent. Suitable substituents are, for example, halogen, CN, 0H, OR', -COR', --COOR', --N'H2, -NHR., NRR", -SR1, wherein R and R" are hydrocarbon radicals such as alkyl, aryl, aralkyl and cyclo-alkyl radicals.

To be useful, it is normally desirable that the compounds of this invention be soluble in the material to be improved. Under normal conditions, some of the compounds otherwise complying with the above general formula are only slightly soluble, for example, in mineral oils because they possess oil solubilizing radicals which are too small or which are present in insufflcient numbers.

Effective oil-solubilizing radicals are in general hydrocarbon radicals possessing at least 6 and preferably 10 or more carbon atoms, such as hexyl, etc., heptyl, octyl, iso-octyl, decyl, dodecyl, tetradecyl, cetyl wax, etc., radicals; aromatic radicals such as phenyl, tolyl, xylyl, benzyl, etc., radicals.

Solubility, however, is not always essential. For example, compounds having extreme pressure properties may merely be suspended in lubricating oils and yet be effective. Suspensions of little soluble or insoluble addition agents may be particularly useful in greases, such as soda soap greases, calcium soap greases, aluminum soap greases, petrolatum greases, etc., with which they may form substantially stable plastic mixtures. The amounts of our compounds to be added to the hydrocarbon oils effectively to improve their properties will vary with the type of, improvement to be achieved. In general, when added to lubricating oils to improve wear resistance, the amounts required normally vary from .1% to 10%, preferably 5% to 5%, depending upon the conditions to be met. If complete solubility of the addition agent is required, its solubility limits frequently set the upper limits of the amounts which can be safely incorporated.

Specific compounds of this group are methyl allophanate and similar allophanates such as propyl allophanate, isopropyl allophanate, tertiary butyl allophanate, amyl allophanate, etc. Also, benzyl allophanate HNC-N-C=O tttt naphthenyl allophanate HNCNC=0 Hittite \CHI H Ha.H:

The allophanates may be obtained, for example, by reacting 1 mol of chlor carbonic esters with 2 mols of urea or thiourea, or by passing cyanic acid vapors into anhydrous alcohols; or by the reaction of carbamic esters or urethanes or thiourethanes with urea chloride, etc., or by the reaction of saturated alcohols with carbamyl or urea chloride.

For example, butyl allophanate was prepared as follows:

Carbamyl chloride was dissolved in benzene and added to a benzene solution of butyl alcohol in the ratio of 2 mols oi carbamyl chloride to 1 mol of alcohol. The reaction took place at room tem-- perature. The mixture was then washed with water to extract hydrogen chloride. The water layer was withdrawn and the remaining benzene solution was evaporated by heating.

If desired, oils containing the improving agents may in addition also contain other addition agents normally added to hydrocarbon oils; thus the compounds of this invention may be used, for example, in gasoline together with antiknock compounds and conventional anti-oxidants, or in lubricating oils together with conventional antioxidants, blooming agents, anticorrosives, extreme pressure compounds, detergents, wedging compounds, i. e., long-chain polar compounds, etc., or in Diesel fuels together with knock suppressors, conventional antioxldants, anti-corrosives. etc. If desired, in order to raise the solubilities of some oi. the compounds, mutual solvents such as alcohols, ethers, amines, etc., of suitable boiling temperatures may be used.

The uses to which some of these compounds may be applied and the highly satisfactory results obtained are further illustrated by the following examples:

Example I A sample of white oil was divided into two portions. Naphthenyl allophanate in an amount of 1% by weight was dissolved in one portion. The doped and undoped oils were then tested on the multiple four-ball machine similar in principle to the Boerlage apparatus described in the magazine, Engineering, vol. 136, July 14, 1933, to determine their ability to prevent wear. This apparatus comprises four steel balls arranged in pyramid formation. The top balls are rotated by spindles against the three bottom balls which are clamped in a stationary ball holder. The balls are immersed in the oil to be tested. Six tests were run simultaneously at a controlled temperature of 130 C. The diameters of the wear scars worn on the three balls forming the base of each pyramid were measured and the average taken as the true indication of wear.

Results were as follows:

Scar diameters Material 130 0., 7 kg.

load

- .Mm. Undoped oii 0.68 il+naphthenyl allophanate 1% 0. 21

Example II Scar diameters Material 0., 7 kg.

load

Unblended oil Blended oil Iii The oil improving agents contemplated by this invention may be single compounds or mixtures of these compounds.

We claim as our invention:

1. An improved hydrocarbon oil selected from the group consisting of Diesel fuel and lubricants containing a minor amount of a compound selected from the group consisting of the esters of allophanic acids and thio-allophanic acids.

2. An improved lubricant comprising a mineral lubricating oil having admixed therewith a minor proportion of a compound selected from the group consisting of the esters of allophanlc acids and thio-allophanic acids.

3. The composition of claim 1 which contains .1% to 10% by weight of the ester.

4. An improved lubricating oil comprising a mineral lubricating oil containing dissolved therein a small amount of an oil-soluble compound selected from the group consisting of the esters of allophanic acids and thio-allophanic acids.

5. An improved lubricating oil comprising a mineral lubricating oil containing dissolved therein a small amount of naphthenyl allophana e.

6. An improved grease composition comprising a soap and a mineral lubricating oil having admixed therewith a small amount of a compound selected from the group consisting of the esters of allophanic acids and thio-allophanic acids.

v7. An improved lubricating oil comprising a mineral lubricating oil containing dissolved therein a small amount of an allophanate having the general formula Illl RzXHX wherein R1 and R2 are radicals selected from the group consisting of hydrogen and hydrocarbon radicals, R3 is a radical having at least 6 carbon atoms selected from the group consisting of aliphatic, alicyclic, aromatic, and mixed cyclic and chain radicals, and X is a radical selected from the group consisting of oxygen and sulfur.

' PAUL R. VAN ESS.

ELLIS R. WHITE. 

